Braking apparatus



sept.' 18, 1923. www@ M.LOUGHEAD BHAKING APPARATUS Filed July 10. 1922 2 Sheets-Sheet 1 Sept. 18, E923..

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M. I OUGHEAv BRAKING APPARATUS Filed July l0. 1922 2 ShGG-Shae 2 lllllHfm" 'named sepa is, 1923.

MALCOLM LOUGHEAD, OF DETROIT,

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MICHIGAN.' Assrenoa, BY Mnsn'n ASSIGNMENTS,

TO HYDRAULIC BRAKE COMPANY, LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

BRAKIN G APPARATUS.

, To all whom t may concern.:

Be it known that I, MALCOLM LOUGHEAD, a citizen of the United States, and resident of Detroit, in the county of Wayne and State of Michigan, have invented a certain new and useful Improvement in Braking Apparatus, of which the following is a full, clear,

-con`c1se,.and exact description, reference being had to the accompanying drawings, forming a part 'of this specication.

This invention relates to braking apparatus, and is herein shown and described as applied to automobiles and particularly to braking apparatus of the fluid pressure operated type. i

The principal feature of the invention resides in means for automatically compensati ing for the wear of braking surfaces so that the` brake operating mechanism retracts through substantially the same distance after wear as when the braking surfaces are in their initialcondition, that is, means are provided so that the brake band or shoe is retracted the same amount after it has become worn as when it is new.

Other features and advantages will appear from time'to time as the description-of thev'invention progresses. l In the drawings, i p. Figure 1 is a sideelevation of the brake drum of an automobile with applicants braking mechanism in position to co-operate therewith, certain parts being shown broken away; Y A t Figure 2 isa section takensubstantially on the' line 2 2 of Figure 1;

` Figure 3 isa longitudinal section through the brake' operating cylinder, pistons, vand mechanism associated therewith, part 'of one ycylinder being shown broken-away; v

Figure 4 is a .section substantially on the f line 41-4'of Figure 3;

Figure 5 shows a modified form of the take-up mechanism, and Figure 6 is a plan view ment shown in Figure 5.

Referring to the drawings justJ described, in `which like reference characters indicate like parts infthe several views,` a steering knuckle 10Aof the frontv wheel of the auto-` mobile is mounted in any suitable manner,

` y such as upon the pivot pin 11, which in turn' is supported between the separated ends 12 and l13 ofthe front axle 14,fusua11yformed integrally withgghe Steel".

an inwardly directed Harige of the-arrange- `parts. In screw thread the upper endl of the shaped cover andspring seat 45, having ing knuckle 10, carries the wheel 15, which These bearings respectively carry the pivot ends of brake shoes 25 and 26, the arrangement being such that the rotation of the shoes about the bearings 23 and 24 moves the shoes toward and away from the inner cylindrical face of the drum 17.

Secured to the left end of the bracket 20, asI viewed in Figure 1, is a cylinder 30 within which a pair of operating pistons 31 are mounted. These operating pistons (see F ig. 3) are provided at their inner ends wlth cup washers 35, held in contact with the inner cylinder wall by means of spring metal cup expanders 33, held in place by metallic washers 36. The piston v31, cup leather 35, sprin spreader 33 and washer 36 are secured tot e piston stem 34 by means of a nut 32 threaded upon the end of the stem 34. The two pistons 31 operating in `opposite ends of the cylinder 304 are identi- "described, ScrewA threaded on the end 'of the cylinder 30 is a collar 37 provided with 38, rojecting somewhat withinthe working sur ace of the 'l cylinder 30. Within the cylinder 30 and flange38 is a bushing 39, having an outwardly directed Han e40 of a diameter permitting it to liewi'tin the cylinder 30, but to enlgage the inner side of the flange 38, thus uniting the outward movement of the bushing. A C-spring lock'ring 41 engages the inner end of the bushing 39, and is I vided with aprojecting end '43 exten l into 4a slot 44V in the collar 37, t0 prevent. relative rotative movement of the bushing 39 and collar 37', but permitting a slight relative' longitudinal movement of 'these bushing 39 is a cup opening in its top through which the'end of the piston stem 34- projects. The bushing -39' is provided on its inner face with an inner conical surface 48, the included angle between the opposite sides of this cone being about 30. The stem 34 has formedfthe'reon ed engagement with l opposite the conical surface 48 a cone shaped' portion 49, the included angle between the opposite sides of which is abo-ut 4. tioned between the surface 48and theoone 49 are a plurality of balls, wedges, or rollers 50 carried by a cage 51. The cage 51 is provided at its upper end with an outwardly directed flange 52, forming a seat for one end of the spring 53, the other end being seated in the top ofthe cup shaped cover 45. About one side of the cover 1s a substantially semi-circular spring or wire 46, the inwardly directed ends 47 of which project through openings in the cover 45, and when the cover is rotated upon the screw threads of the bushing 39 these projecting ends 47 engage the under side of the flange 52 and lift t e cage 51, permitting the stem 34 to be returned to its normal position in relation to the sleeve 39, this action being necessary when a new brake band is provided, as will be hereinafter more fully described.

The outer surfaces of the brake shoes 25 and 26` are -provided with brakeliners 54. which are normally retracted out of engagement with the brake drum 17 by means oil tension springs 55, the opposite ends of which are secured in holes in the lugs 56 on the brake shoes. Near the free ends of the brake shoes 25 and 26 are provided bracket members 57, having openings 58 therein. These openings are each provided with a ball 59 adapted to be engaged by the end of the stem 34 when the pistons 31 are pressed outwardly by fluid pressure. Communicating with the part of the cylinder 30 between the pistons 31 is a tube 60 supported by the bracket member 61, this tube being extended to a suitable source of fluid pressure, not herein illustrated. This source of pressure may be of any desired character, wherein a reserve supply of fluid is provided for automatically supplying additional amounts of fluid to the system to compensate for leakage or for different piston positions as they may be assumed in the wear of brake 1inings. In the foregoing description, the term brake shoe is intended to include such` other commonly known devices for the application of brake pressure, such as flexible brake bands and disks. The operation of the device shown in Figs. 1 to 4 is as follows: Assuming that the brake linin 54 is new, and of maximum thickness, as indicated in Fig. 3, and that the take-up mechanism is in -a position to permit the stem 34 to be fully retracted, asindicated in Fig. 3, when fluid under pressure is forced through the tube 60 into the cylinder 30, between the adjacent ends of the pistons 31, the pistons move from their normal positions causing `the stems 34 to forcibly engage the balls 59, thus operating to swing the free ends of the brake shoes 25 and 26 to force the brake Posilinings 54 into 'firm engagement with the inner face of the drum 17.

As the brake lining 54 becomes worn, the brake shoes 25 and 26 will be moved further toward the brake drum 17 in order to cause the brake lining to effectively engage the drum. If no take-up means were provided, either automatic or otherwise, a`

the drum when the lining is worn as is re-- quired for a single braking -pressure when the lining is new. With this arrangement, the operator providing, fluid pressure by the operation of a piston in the main fluid pressure cylinder moves the brake linings into contact with the brake drums through the same foot movement when the linings are worn as when the linings are new.

Assuming now that the lining 54 is materially worn: If fluid under pressure be forced into the cylinder 30, through the tube 60, the pistons 31 will move in opposite directions than before. After the pistons have moved a relatively short distance, the flange 40 on the bushing 39 will engage the inwardly directed flange 38 preventing the further movement of the bushing 39 in relation to the cylinder. Assuming now that the operator applies a slightly greater foot pressure than he has before applied, the stem 34 will continue to move until the brake has been completely set. When the stem 34 thus continues its movement, the space between the inner wall of the bushing 39 and the outer wall of .the cone 49 will be slightly enlarged. because of the difference in angles of slope between the inner wall of the bush- 'ing 39 and theouter face of the cone 49.

With this space between the cone and the bushing thus enlarged, the balls 50 are forced to a new position by means of the spring 53, so that when the brake is again retracted the stems 34 and pistons 31 will not move to the same positions which they occupied in retracted condition just prior to this particularly high brake setting compression. The base of the cover 45, where it now engages the outside of the flange 38, limits the retractile movement of the stem 34.

In the ordinary operation of setting the brakes, the movement of the stem 34 and piston 31 is limited to the clearance between the flange 40 of the bushing 39 and the flange 38 on the collar 37, but when. as above pointed out, the brake lining is slightly worn through continuous application of the brakes,

pressure, there will be a slight relative movement between the stem 34 and the bushing 39, which movement will not again occur the movement of the d of the until wear has without 1n any again reduced the thickness of the brake lining, or until the operator has applied a still greater pressure to the fluid. The spring 62, positioned between'the piston 31 and the bushing 39 serves merely to hold that bushing in firm contact with the balls to prevent the shifting of the relative positions of the bushing 39 and the stem 34 through vibration, and insures bushing 39 with the stem 34 when the brakes are being applied way interfering with the automatic readjustment of positions between the stem and bushing as the brake lining wears. With the construction and operation just described in mind, it will be understood that the piston 31 and its stem 34 77 gradually move outwardly as the brake lining wears until, with the brake lining substantially all worn away, the end of the stem 34, will protrude an eighth of an inch or more beyond the top of the cover 45.

In Figures 5 and 6 is shown a modification take-up means in which a ratchet is employed. This mechanism operates insubstantially the same manner 4as that shown in detail in Figure 3,`except, due to the'fact that a ratchet instead of the ball clutch is employed, the take-up occurs at definite inengagement with the 'der 65 is a collar 70 -tervals, instead of continuously.

Figure 5, indicates' Referring now to the cylinder and 66 the brake operating piston slidably mounted therein. Rigidly secured to the piston 66 is a stem 67. Mounted about the stem 67 is a sleeve 68` which has its opposite faces flattened andv provided with ratchet teeth 69. In screw threaded upper end of the cylinhavingthe inwardly directed flange 71. Positioned within the flange 71 is a collar 72 provided with a .flange 73 which yextends outwardly4 beneath the inwardly directed flange 71.

Atl4vare shown spring locking arms, each '-3.3 of which has a downwardly directed inner end 75 positioned within an opening in the flange 73. The outer end of each of the spring arms 74 is clamped between'the upper end of the cylinder 65 and the flange These arms 74 .operate to normally maintain the sleeve 72 in its lowermost .position, and also actyto prevent rotation of the sleeve 72 when the collar or nut 76 is screwed onto the upper end of the collar 72. Rigidly fixed to the collar 72'is a pair of pawl members 77 which are adapted to co-operate with the'ratchet teeth 69 on the sleeve 68. The action of the device shown in detail in Figure 5, as previously stated. is substantially the same as that-shown in Figure 3.

Assuming that the brake band has worn,

1f now the piston 66 be moved upwardly,

.ther movement of .to the cylinder 65.

after the initial movement the flange 73 will engage the flange 7l and prevent furthe sleeve 72 vin relation The stem 67, however', will continue to move and will carry with it the sleeve 68 with the ratchet teeth thereon. lf the brake lining has worn sufficiently, the stem 67 will move in relation to the sleeve 72 a distance sufficient to permit the pawls 77 to engage back of the'next ratchet teeth 69. If, however, the brake band has worn only a small amount, the pawls 77 will ride up on the inclined surfaces of the ratchet teeth 69 but will not move far enough Ato permit them to drop back of the next tooth in the series.

When it is desired to restore the parts to their-,normal position, as when the brake lining is replaced by a new one, the pawls are retracted in any desired manner, as by the use of a pair of screw drivers, and the plunger 6 7 is permitted to move downwardly in relation to the sleeve 72.

`While in the above description and in the drawings, certain specific details have been disclosed, it is to be understood that applicant contemplates many modifications in the particular arrangement of the various parts. It is, therefore, to be understood that the invention is to be limited merely by the scope of the appended claims.

aving thus described my invention, what I claim as new and'desire to secure by Letters Patent ofthe United States is:

1. In braking mechanism, a pair of relatively movable friction members'adapted to be forced into engagement with one another for braking purposes. an operating member for creating pressure between said relatively movable members, a stop for limiting the separation of saidv members. and an automatic take-up co-operating with said stop to compensate for wear between the pair of braking members so that their relative movement away from one another will be substantially the sameafter wear has occurred between them as in their'initial condition.

2. An auotomatic adjusting device for taking up wear in braking mechanism comprising a movable wear member, a piston operatively connected therewith, mechanism movable with the piston for applying the brakes under ordinary conditions, said mehanism comprising parts movable relative to one anotherl for taking up wear, said parts being shaped with `a tapering space between them, a wedging member in said space, a spring4 tending to force said Wedgmg member into the narrower part of saidy stop for one of said members limiting its movement in'each direction, all functionin so that when one member moves relative to the other member in one direction, to compensate for wear, the wedgin'g member prevents it from moving in a retrograde direction.

3. In braking mechanism, a brake drum, a brake shoe, a

lining therefor, means for forcing said lining into engagement with said drum7 a stop for limiting the movement of said shoe and said means= a take-up associated with said stop, and means for automatically adjusting said take-up so as to permit a substantially equal retractile movement of said forcing means regardless of the condition of wear of said lining.

4. In braking mechanism, a brake drum, a wear member, 'a stem for forcing said wear member into engagement with said drum, a. stop for limiting the retractile movement of said stein, a take-up associated with said stem, and means for automatically adjusting said take-up so as to permit a substantially equal retractile movement of said stem regardless of the condition of said wear member.

5. In braking mechanism for vehicles,- a brake drum, a wear member, a stem for forcing said wear member into engagement with said-drum, a bushing positioned vabout said stem. the inner surface of said bushing and the outer surface of said stem being formed to provide a tapered space therebetween, a wed,i r,ing member positioned within said space, means tending to force said wedging member toward the restricted end of said space, and means for limiting the movement of said bushing in both directions.

6. In braking mechanism for vehicles, a brake drum, a -brake shoe, a lining therefor, a stem for forcing said lining into engagement with said drum, a cylinder, a piston within said cylinder for operating said stem,

a take-up associated with said stem, and

means for automatically adjustin said takeiip so as to permit a substantial y equal retractile movement of said stem regardless of the condition of wear of said lining.

7. In braking mechanism, a rotating brake member, a relatively fixed wear member, a stem for actuating said wear member, abushing positioned about said stem7 means for limiting the movement of said bushing in both directions, and automatically adjustable means co-acting with said bushing and stem for preventing retrograde movement of said stem relative to said bushing.

8. In brakin mechanism for vehicles, a brake drum, a rake shoe, a lining therefor, a. cylinder, a piston movable within said cylinder, a tapered stem carried by said piston and having a part arranged to engage said shoe, a tapered abutment positioned adjacent said stem, means for limiting the retractile movement of said abutment in bot-h vdirections, and a take-,up clutch c'o-operatively joining said tapered abutment and 'tapered stem so as topermit movement of said stem past said abutment prevent movement of the stem past said abutment in the opposite direction.

k9. In braking mechanism for vehicles, a bra-ke drum, a brake shoe1 a lining therefor, a' cylinder, a piston within said cylinder, a stem carried by said piston and arranged to engage said brake shoe, a bushing positioned about said stem, means for limiting the backward and forward movement of said bushing, the inner surface of said bushing and the outer formed to provide a tapering space therebetween, a series of ballswithin said space, a ball cage engaging said balls, and a spring engaging said ball cage and tending to force said balls toward the restricted end of said space.

10. In braking mechanism, a brake drum, a brake shoe, a cylinder, a piston within said cylinder, a stem carried by said piston and arranged to engage said brake shoe, a bushing positioned about said stem, means for limiting the backward and forward movement of said bushing, the inner surface of said bushing and the outer surface of vsaid stem being formed to provide a tapering space therebetween, a ball cage within said space, 'a series of balls carried by said cage and arranged to engage the adjacent surfaces of said bushing and stem, a spring engaging said ball cage and'tending to force said balls toward the restricted end of said space, and a spring engaging said bushing and tending to move it relative to said stem, said balls operating to prevent such relative movement.

11, In braking mechanism for vehicles, a brake drum, a brake shoe, a cylinder, a piston within said cylinder, a stem carriedby said piston and arranged to engage said shoe, a bushing surrounding4 said stem, said bushing and stembeing formed to provide a space therebetween tapering toward said piston, a ball cage within said space, a plurality of balls carried by said cage, a spring engaging said 'cageand tending to force said balls toward the restricted .end of said .'11s

space, and a spring engagin said bushing and tending to force it in t e opposite' direction.

In witness whereof, I hereunto subscribe my name this 14th day of June, 1922.

MALCOLM LOUGHEAD.

Witnesses:

EMILE J. BOURGEOIS, DAGMAR PETERSON.

in'one direction, butito f surface of said stem being 

